Mobile and Embedded

You begin by finding out if there is a PostGreSQL driver that works on that platform. The normal drivers may work without problem, but I'd start there anyway. Only after the answer to that one is "yes", Qt comes into the picture at all.

OpenVG works fine with stylesheets on Symbian^3 devices. Perhaps you are using OpenVG 1.0 instead of 1.1 and that is causing some problems? I'm not sure we have done much testing on 1.0. Is the problem specific to stylesheets? If so, perhaps you could use QML instead. It is far more efficient for custom UI's than using QWidget + stylesheets.

K , I Try them now...Thank you But I also have some problems about OpenGL in the same project ... Can you help me with that... Check this post... "Beginning in Qt with OpenGL":http://developer.qt.nokia.com/forums/viewthread/6173

Imaging scaling is very expensive and memory constrained in low memory devices like handhelds. Why don't you use svg instead of png. They scale to the target resolution and work like a charm in low memory targets. If you still prefer to use png files, please scale it yourself and provide an image cache that resides on the disk rather than on RAM. If you downscale try doing a "cheat scale":http://labs.qt.nokia.com/2009/01/26/creating-thumbnail-preview/

I've been experimenting with reading raw linux input events from my mouse. I can interpret the event and post a QMouseEvent to my QDeclarativeView::viewport() widget. Those events make it to my QML. It would be awesome if I could set a keyboard modifier on my QMouseEvent so the QML could distinguish the mouse event from a touch event. In my Mouse Reader: @ QMouseEvent m(QEvent::MouseMove, QCursor::pos(), view->mapToGlobal(QCursor::pos()), Qt::NoButton, Qt::NoButton, Qt::MetaModifier); // Why does Qt discard this event? QApplication::sendEvent(view->viewport(), &m); @ In my QML: @ MouseArea { anchors.fill: parent hoverEnabled: true onPositionChanged: { if(mouse.modifiers & Qt.MetaModifier) { // mouse.modifiers is NEVER set console.log("++ Mouse Move!" + " " + mouse.button + " " + mouse.modifiers + " " + mouse.buttons) } else { console.log("++ Touch Move! " + " " + mouse.button + " " + mouse.modifiers + " " + mouse.buttons) } } } @ But I never get Mouse Moves, only Touch Moves. Qt seems to discard a QMouseEvent(QEvent::MouseMove) with the keyboard modifier. This scheme works for my mouse press/release. I can distinguish those using mouse.modifiers. Does anyone know why Qt discards MouseMove's when the keyboard modifier is set? Thanks, Matt

@leon: thank you very much! I'll try it.

[quote author="mario" date="1305786992"]Well, there are two major points in using Qt as I see it. Platform independent. You can write code for multiple platforms using the same code base. It's not dependent on having a specific OS installed. Android code can only execute in a dalvik/android-environment. Language independent. This is even better than the first point, at least for me. You can choose to develop in many different languages such as Python, Java, C#, Ruby and C++ (and there sure more options). Android is basically Java-only. I'm sure their scripting supports are actually executing by the dalvikvm. Then I would also add that the Qt-api:s feels more generic and Android is more tailored for specific situation where you need to embedded contact manager, calendars etc in your application.[/quote] Yes, a lot of language bindings. And as you says, Qt is more generic, you can use it create more beatiful things, while Android, i think maybe it's a little bit tailored. But, anyway, it depends.

[quote author="gaucho" date="1305642401"]ok, if you know i can do these thigs i'll try. (i'll let you know). may be i remember it wrong, but it seems to me that multimedia kit doesn't allow you to select the output device, but only the output "type".[/quote] you can get the device list via: QList<QAudioDeviceInfo> QAudioDeviceInfo::availableDevices ( QAudio::Mode mode ) and use QAudioOutput to do the play work. You can also specify a output format. The only disadvantage i think, is the API didn't support setVolume function.

[quote author="leon.anavi" date="1305612824"]Hi Luca, Lana, I have tested Qt Simulator a minute ago and I had the same problem. According to a "thread at Forum Nokia":http://discussion.forum.nokia.com/forum/showthread.php?223306-moved-Why-i-see-my-menu-at-Qt-simulator-control this is the way the simulator works currently. :( I have never been fan of simulators and this is another proof that is better to work with real device. Best regards, Leon [/quote] Thanks, so the Simulator simulate a broken phone... :-)

"Origaniser":http://doc.trolltech.com/qtmobility-1.1.0-beta/organizer.html#calendar-features module in Qt Mobility will help you to do that if you are targeting mobile platforms. If you are targeting desktop modules, then you should find a proper backend to do that, else write one using Qt itself.

Hi Brijesh, I am sorry for the late response. Now, I try early version of tslib to build this project. It works. I don't know why using tslib v1.0 will cause "Segmentation fault" but the early version won't at my target.

Symbian way of writing the code is not like any other platforms. Memory Management is an integral part of the OS architecture. If you use resource hungry classes, make sure you reuse them rather than creating them very often. Also prefer to create using new operator rather than creating on the stack, because stack is very precious. If you run on a Symbian emulator (you will get S60 5th edition SDK from forum nokia), you can get the memory leaks and "ALLOC" errors with the memory address. After that you can use HookLogger to detect where exactly the leak has occured ( see http://wiki.forum.nokia.com/index.php/Detecting_memory_leaks_with_HookLogger about hooklogger). Qt classes on Symbian do have some memory leaks especially resource handle classes, so you can count them too for your issue.

It could open more possibilities for C/C++ developers if Blackberry would support/develop C/C++ compilation for they's devices.

I know it is an old thread but anyway if you still have this problem you can check the following article at wiki: "QWidget Semi-transparent Background Color":http://developer.qt.nokia.com/wiki/QWidget_Semi-transparent_Background_Color I have tested it myself on Symbian^3. Cheers, Leon

Thanks for the info. I am looking at various suggested links. Seems another set of huge downloads are needed. It would have been nice to integrate just Meego to Qt SDK

ok thanks to all of you..now its clear.. :)

In fact I just guessed that. I solved by creating the header file. Thanks!